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Manuscript Number: IJRM-D-11-00481R3
Title: A Comparison of Different Pay-Per-Bid Auction Formats
Article Type: Full Length Article
Corresponding Author: Dr. Ju-Young Kim,
Corresponding Author's Institution: Goethe-University Frankfurt
First Author: Ju-Young Kim
Order of Authors: Ju-Young Kim; Tobias Brünner; Bernd Skiera; Martin
Natter
Abstract: Pay-per-bid auctions are a popular new type of Internet auction
that is unique because a fee is charged for each bid that is placed. This
paper uses a theoretical model and three large empirical data sets with
44,614 ascending and 1,460 descending pay-per-bid auctions to compare the
economic effects of different pay-per-bid auction formats, such as
different price increments and ascending versus descending auctions. The
theoretical model suggests revenue equivalence between different price
increments and descending and ascending auctions. The empirical results,
however, refute the theoretical predictions: ascending auctions with
smaller price increments yield, on average, higher revenues per auction
than ascending auctions with higher price increments, but their revenues
vary much more strongly. On average, ascending auctions yield higher
revenues per auction than descending auctions, but results differ
strongly across product categories. Additionally, revenues per ascending
auction also vary much more strongly.
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A Comparison of Different Pay-per-Bid Auction
Formats
Ju-Young Kim, Tobias Brünner, Bernd Skiera, and Martin Natter
Ju-Young Kim, Assistant Professor
Goethe-University Frankfurt, Faculty of Business and Economics, Department of Marketing,
Grueneburgplatz 1, 60323 Frankfurt am Main, Germany
Phone: ++49-69-798-34634, Fax: ++49-69-798-35001, E-Mail: [email protected]
Tobias Brünner, Assistant Professor
Goethe-University Frankfurt, Faculty of Business and Economics, Department of Management und
Microeconomics, Grueneburgplatz 1, 60323 Frankfurt am Main, Germany
Phone: ++49-69-798-34831, Fax: ++49-69-798-, E-Mail: [email protected]
Bernd Skiera, Chaired Professor of Electronic Commerce
Goethe-University Frankfurt, Faculty of Business and Economics, Department of Marketing,
Grueneburgplatz 1, 60323 Frankfurt am Main, Germany
Phone: ++49-69-798-34649, Fax: ++49-69-798-35001, E-Mail: [email protected]
Martin Natter, Chaired Professor of Retail Marketing
Goethe-University Frankfurt, Faculty of Business and Economics, Department of Marketing,
Grueneburgplatz 1, 60323 Frankfurt am Main, Germany
Phone: ++49-69-798-34650, Fax: ++49-69-798-35001, E-Mail: [email protected]
==========================================================
ARTICLE INFO
Article history:
First received on November 2, 2011 and was under review for 10 months
Area Editor: Sandy D. Jap
============================================================
Acknowledgements
We thank Jochen Reiner and the participants of presentations of this paper at the University of New
South Wales and the Monash University. We appreciate the many valuable suggestions and comments
from the previous editor, Marnik Dekimpe, the editor, Jacob Goldenberg, as well as the anonymous
reviewers.
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A Comparison of Different Pay-per-Bid Auction Formats
Abstract
Pay-per-bid auctions are a popular new type of Internet auction that is unique because a fee is
charged for each bid that is placed. This paper uses a theoretical model and three large empirical
data sets with 44,614 ascending and 1,460 descending pay-per-bid auctions to compare the
economic effects of different pay-per-bid auction formats, such as different price increments and
ascending versus descending auctions. The theoretical model suggests revenue equivalence
between different price increments and descending and ascending auctions. The empirical results,
however, refute the theoretical predictions: ascending auctions with smaller price increments
yield, on average, higher revenues per auction than ascending auctions with higher price
increments, but their revenues vary much more strongly. On average, ascending auctions yield
higher revenues per auction than descending auctions, but results differ strongly across product
categories. Additionally, revenues per ascending auction also vary much more strongly.
Keywords: pay-per-bid auction, bidding fees, online marketing, electronic commerce, pricing,
auction
FINAL APPROVED MANUSCRIPTClick here to view linked References
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1. Introduction
Pay-per-bid auctions offered by retailers, such as Quibids, Bidcactus and MadBid, are
exciting, fast-paced business-to-consumer online auctions that are attracting significant interest
from consumers, popular press and start-up companies. Unlike other well-known auctions sites,
such as eBay, pay-per-bid auctions charge a fee for each bid that is placed, regardless of whether
one wins the auction. Additionally, a bid placed increases the price by a certain increment that is
chosen by the auctioneer.
At first glance, fee-based bidding does not sound attractive because the bidder encounters the
risk of having to pay bidding fees without winning the auction. However, the compelling part of
this model is that the bidders who win an auction can potentially save more than 99% off the
current retail price (CRP) of the product. For example, on MadBid.com, a new MINI One car was
sold for €8.47 rather than its retail price of €15,000. Similarly, a new Kymco scooter, which
regularly sells for €1,240, was sold for €0.40.
Popular magazines, newspapers and online blogs are replete with heated discussions
regarding this emerging type of auction.1 Although some commentators are enthusiastic about the
attractive deals offered by pay-per-bid auctions and how enjoyable they are, others strongly warn
consumers against participating in them. Such commentators point to potentially huge losses for
1 For magazines, see for example, Last, Jonathan V. (February 23, 2009) “Take a chance on an auction; Swoopo and
the rise of Entertainment Shopping” in The Weekly Standard; (December, 2011) “Can you buy products dirt cheap on QuiBids? Behind the hype” in Consumer Reports. For newspapers, see for example, King, Marc (January 28, 2012) “How penny auction websites can leave you with a hole in your pocket” in The Guardian; Zimmerman, Ann (August 17, 2011) “Penny auctions draw bidders with bargains, suspense” in The Wall Street Journal; Choi, Candice (June, 24, 2011) “Penny auction sites could cost a chunk of change” in The Washington Times; ConsumerReports.org (December 2011) “With penny auctions, you can spend a bundle but still leave empty-handed”; McCarthy, John (June, 2, 2011) “Penny auctions promise savings, overlook downsides” in USA Today; Migoya, David (January 25, 2010) “BARGAIN BIDDERS On penny auction sites, buyers can get gift cards for a fraction of face value -- or pick up a new addiction” in The Denver Post; and Thaler, Richard H. (November 15, 2009) “Paying a Price For the Thrill of the Hunt” in The New York Times. For blogs, see for example, http://www.foxbusiness.com/personal-finance/2012/07/10/online-auction-virtual-bargain-or-real-rip-off/, http://www.scambook.com/blog/2012/07/penny-auction-fraud-alert-how-you-can-lose-by-winning/, http://www.usatoday.com/tech/columnist/kimkomando/2011-05-13-komando-penny-auctions_n.htm, http://www.thesimpledollar.com/2010/11/20/a-deeper-look-at-quibids-and-why-i-dont-think-its-worth-it/, and http://www.theregister.co.uk/2009/01/02/swoopo_startrup/.
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bidders as a result of the high bidding costs, which can easily be in the range of several hundred
dollars per auction. However, all commentators have based their conclusions on a fairly limited
number of observations, some of which are quite anecdotal.
Furthermore, auctioneers lack knowledge regarding how different auction formats influence
their profitability. They frequently adjust their auction formats, and many auctioneers, such as the
pioneer of this type of auction, Swoopo, have become bankrupt. Thus far, only a few researchers
have analyzed pay-per-bid auctions by developing theoretical models (Augenblick, 2012; Gallice,
2011; Platt, Price, & Tappen, 2013) and by testing these models with actual sales data. Others
have empirically compared the effect of the buy-now price feature on bidders' behavior in
ascending penny auctions (Reiner, Natter, & Skiera, 2014). Analysis of the economic effects of
different pay-per-bid auction formats that differ in the sizes and signs of price increments has
thus far been neglected. We are the first researchers to close this gap.
We aim to theoretically and empirically assess the economic effects of different pay-per-bid
auction formats. In particular, we compare different price increments (penny vs. ten-cent
auctions) of ascending auctions as well as of ascending and descending pay-per-bid auctions.
Therefore, we adapt and extend previous theoretical models, formulate predictions regarding the
influence of auction formats on auctioneer revenues and empirically analyze them using three
unique and large empirical data sets. Our data include the results of 44,614 ascending pay-per-bid
auctions and 1,460 descending pay-per-bid auctions along with 1,142,738 bids.
The remainder of this manuscript is structured as follows. In the next section, we compare the
most prominent pay-per-bid auctioneers and outline previous literature on pay-per-bid auctions.
In Section 3, we describe our theoretical models and formulate predictions for the economic
effects of different pay-per-bid auction formats. We investigate the economic influence of
different formats of ascending pay-per-bid auctions in Section 4 and those for descending pay-
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per-bid auctions in Section 5. In Section 6, we compare the results of ascending and descending
auctions. Section 7 summarizes our findings, discusses implications and points to topics for
future research.
2. Pay-per-Bid Auctions
Pay-per-bid auctions are characterized by the association of bidding with tangible costs.
Using traffic data (May 5 to August 5, 2013) from Alexa.com, Table 1 outlines some of the
largest pay-per-bid auctioneers (with a reach of more than 0.001% of all global Internet users)
and the characteristics of their auctions. All ascending auctioneers begin with a price of zero, but
they differ by how much they change the price for each bid. Quibids offer various price
increments that range from €0.01 to €0.15, whereas others increase the price by only €0.01. The
start price of descending auctions is equal to the CRP. Bidding fees are substantial in all auction
formats, ranging from €0.50 to €1.50.
Table 1
Comparison of the Most Popular Pay-per-Bid Auctions
Provider Quibids Dealdash MadBid Beezid Bidcactus ClicxaBids vipauktion
Auction
Format ascending ascending ascending ascending ascending descending descending
Starting
Price $0.00 $0.00 £0.00 $0.00 $0.00 CRP CRP
Bidding Fee $0.60 $0.60 £0.25-£1.20 $0.55-
$0.90 $0.75 varies €1.00-€2.00
Price
Increment
$0.01-
$0.20 $0.01 £0.01 $0.01 $0.01 varies €0.40
Operating
Countries
US/
Europe/
Canada/
Australia
US only
UK/Spain/
Germany/Italy
/ Ireland
US, ships
worldwide
US, also
ships to
Canada
US/Ireland Germany
Market
Share May-
Aug 2013
75.69% 7.60% 5.06% 3.46% 2.95% n.a. n.a.
(% reach) 0.050 0.005 0.003 0.002 0.002 n.a. n.a.
Market share based on reach between May and Aug 2013; % reach = percentage of all Internet users visiting this
site; CRP: current retail price, with all prices in local currencies; n.a. = not available
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2.1. Description of Pay-per-Bid Auctions
Figure 1 is a graphic illustration of ascending and descending pay-per-bid auctions. An
ascending auction opens with a starting price that is usually €0.00. Each bid increases the price,
and the bidder must pay for each bid. For example, in a typical auction at Quibids, each bid costs
approximately €0.40 and increases the price by €0.01. Additionally, placing a bid delays the end
of the auction by a countdown time (often 20 seconds). The auction ends when the countdown
time has elapsed without an additional bid. The last bidder wins the auction and has the option to
purchase the product from the auctioneer for the price of the final bid.
In contrast, in a descending auction, such as those offered by vipauktion, each placed bid
costs €1.00 to €2.00 and decreases the current price by €0.40. After placing the bid, the bidder
receives information regarding the current price. Hence, in a descending auction, the bid is not
simply a bid in the narrow sense, as it is not a bid on a specific price. However, every placed bid
reveals additional information regarding the current price. When the bidder accepts the current
price, the product is purchased, and the auction ends. Otherwise, the auction continues, and the
bidder can wait and place an additional bid to reveal information regarding an updated (lower)
price.
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Figure 1
Graphic Illustration of Ascending and Descending Pay-per-Bid Auctions
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2.2. Previous Literature
Research on online auctions has recently been increasing in popularity (Barrot, Albers,
Skiera, & Schäfers, 2010; Dholakia, Basuroy, & Soltysinski, 2002; Haruvy & Popkowski
Leszczyc, 2009; Jap & Naik, 2008; Pinker, Seidmann, & Vakrat, 2003). Ever since the broad
acceptance of the Internet online auctions such as eBay have become more popular. As a
consequence, a variety of auction formats have emerged, such as name-your-own-price auctions
(Amaldoss & Jain, 2008; Hinz & Spann, 2008; Spann, Skiera, & Schäfers, 2004) and pay-per-bid
auctions.
Knowledge of ascending pay-per-bid auctions in particular is currently growing. Augenblick
(2012), Hinnosaar (2010) and Platt et al. (2013) were the first researchers to provide theoretical
models of ascending pay-per-bid auctions. Independently of one another, they show that any
subgame perfect equilibrium of an ascending pay-per-bid auction that receives more than one bid
must be in mixed strategies. A mixed strategy in this context means that bidders randomly choose
between bidding and not-bidding in each round of the auction.
According to their theoretical models, Augenblick (2012) and Platt et al. (2013) find
deviations with actual revenues being well above expected revenues. Therefore, Platt et al. (2013)
extend their model to allow for risk preferences (risk-loving/risk-averse vs. risk-neutral), which
leads to expected revenues that better match actual revenues. Byers, Mitzenmacher, and Zervas
(2010) build on the theoretical model developed by Platt et al. (2013) and Augenblick (2012) and
analyze information asymmetries across bidders. Their model shows that when bidders
underestimate the true number of bidders, the duration of the auction and thus the auctioneer’s
revenue increases. In an experimental study, Caldara (2012) shows that neither risk-loving
bidders nor incorrect beliefs regarding the parameters of the auction (such as the number of
bidders) are necessary for observing revenues that exceed the product’s value and thus the
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expected revenues. Moreover, he finds that revenues move closer to the revenues of the
theoretical model as bidders gain experience. The important role of experience is supported by
Wang and Xu (2013), who analyze bid-level data from a large ascending pay-per-bid auction
website and show that losing bidders stop participating in these auctions while others learn,
continue to bid and make profits.
By contrast, there is little research on descending pay-per-bid auctions, as Gallice (2011) is
the only researcher who derives equilibrium bidding behavior in descending pay-per-bid
auctions. He shows that in equilibrium, only two situations can arise: either the product is
purchased at the starting price, or no bid occurs. The reason is that if at least one bidder is willing
to buy at the starting price, then this bidder will buy immediately; if no bidder is willing to buy at
the starting price, then no one will ever observe the price, and the product will not be sold.
However, contrary to his prediction, Gallice (2011) finds (similar to what ascending pay-per-bid
researchers have found) that actual revenues were well above the expected revenues. He explains
the deviations with bounded rationality of the bidders.
Thus far, there is no study that compares the averages and variances of actual and expected
revenues among pay-per-bid auctions with varying sizes (penny vs. ten-cent) or signs (ascending
vs. descending) of price increments. In the following, we will present the theoretical models on
which our empirical analysis is based.
3. Economic Analysis of Pay-per-Bid Auctions
For both auction formats, ascending and descending pay-per-bid auctions, we use the same
assumptions as Platt et al. (2013) and Augenblick (2012). These assumptions lead to a theoretical
model that is similar to the model that Platt et al. (2013) and Augenblick (2012) developed for the
ascending auction and to a special case of the theoretical model that Gallice (2011) suggested for
the descending auction.
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3.1. Model Assumptions
Risk neutral bidders: We assume throughout the study that there are n risk-neutral bidders.
However, the assumption of risk neutrality is not innocuous. Platt et al. (2013) show that
expected revenues of ascending pay-per-bid auctions are decreasing in the degree of risk
aversion. Expected revenue is lower (higher) when bidders are risk averse (loving) than when
they are risk-neutral. Platt et al. (2013) find evidence for modest degrees of risk-loving
preferences. However, the reported range of estimated degrees of risk aversion is wide (varying
between -0.0017 (for $1,000) and -0.03 (for the 50 free bids)), and the degree of risk aversion
appears to depend on the product that is auctioned off. Moreover, in contrast to ascending pay-
per-bid auctions (Reiner, Brünner, Natter, & Skiera, 2014; Platt et al., 2013,) there are no
estimates of the risk attitudes of bidders in descending pay-per-bid auctions. Therefore, we
assume risk-neutral bidders in the theoretical models of all auction formats.
Common valuations of products: Each bidder values the product to be auctioned off at the
commonly known willingness-to-pay (WTP) of v. For art, antique furniture and other collectors’
items that are typically associated with auctions, the assumption that all bidders value a product
equally is certainly improbable. However, because the products that are offered at pay-per-bid
auctions are brand new products that are readily available at alternative shopping websites or
high street retailers, we believe that the assumption is reasonable. Augenblick (2012) shows that
a theoretical model in which bidders have independent private valuations converges to the full
information common valuation case as the differences in valuation decrease.
Current retail price (CRP) = willingness-to-pay (WTP): Pay-per-bid auction providers
display a product’s CRP for the entire time of the auction. This price is often higher than the
prices that other shopping websites post for the same product. For example, Augenblick (2012)
reports that the average price of Amazon is only 79% of the CRP. However, bidders’ WTP is in
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turn estimated to be 15% to 65% higher than the Amazon price (Platt et al., 2013). These
numbers lead to a range for the WTP that is between 90.85% (1.15 x 79%) and 130.35% (1.65 x
79%) of the CRP. Because this value is posted prominently on the auction website, it may also
serve as an anchor. Therefore, we use the CRP as a proxy for the WTP, which should work well
for cash or vouchers because the CRP is simply equal to the amount of cash or the monetary
value of the voucher.
3.2. Economic Analysis of Ascending Pay-per-Bid Auctions
In the following, we present the baseline model of the ascending pay-per-bid auction
developed by Platt et al. (2013) and Augenblick (2012). There are n bidders. The ascending
auction starts at a price of zero. Each bid increases the price by d and costs b. After each bid, all
bidders (except the current highest bidder) decide whether to place a bid or not. If several bidders
decide to bid, then one of them is randomly selected, pays the bidding fee b and becomes the new
highest bidder. The current price is raised by d. Thus, after q bids, the auction price is qd. If none
of the bidders places a new bid, then the auction ends, and the current highest bidder buys the
product for the current auction price.
Platt et al. (2013) and Augenblick (2012) show that there is a symmetric subgame perfect
equilibrium in mixed strategies; after q-1 bids, every bidder who is not the current highest bidder
places a bid with probability :
(1)
To obtain an intuition for the equilibrium strategy in equation (1), let us first argue why the
behavior of bidders is stochastic or, more technically, why there is no symmetric equilibrium in
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pure strategies. Suppose that the number of bids is low, such that the WTP for a product exceeds
the current price plus the bidding cost: v > qd + b. If a bidder knew that all other bidders would
not bid, then she would bid and make a bargain. As a result, a situation in which no bidder places
a bid cannot be an equilibrium. Similarly, when all bidders always place a bid early in the
auction, it will become advantageous for a bidder to wait and allow the other bidders to pay the
bidding fees until there is a positive probability that the auction will end. Thus, a situation in
which all bidders always bid is also not an equilibrium. Therefore, the only symmetric
equilibrium is in mixed strategies. The probability of making a bid is determined such that
bidders are indifferent between placing a bid and not placing a bid.
The parameter in the equilibrium strategy in equation (1) is the probability that at least one
bidder will place a bid in the first period. This parameter is not uniquely determined in
equilibrium. However, if no one places a bid in the first round, which occurs with probability
, then the auction ends, and the auctioneer can immediately set up a new, identical auction.
If, again, no bidder places a bid, then the auctioneer can restart the auction repeatedly until there
is at least one bid in the first round. In our data set, we only have auctions that attracted at least
one bid. Therefore, we set to concentrate on auctions that have at least one active bidder.
Platt et al. (2013) show that in an ascending auction with WTP v, these bidding strategies lead
to the following expected value and variance of the revenue of one auction Ra:
(2a)
(2b)
The result for the expected revenue can be obtained by the following logic. The total surplus
of auctioneer and bidders together is then the WTP, v. However, in equilibrium, bidders are
indifferent between placing a bid and not bidding. Consequently, bidders are also indifferent
between placing no bid at all and actively participating in the auction. Because placing no bid at
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all yields a utility of zero, participating in the auction must also have an expected utility of zero.
If the bidders’ expected utilities are zero, the entire surplus accrues to the auctioneer and thus, the
auctioneer’s expected revenue is v. The expression for the variance of revenues in equation (2b)
is the variance of a continuous approximation of the distribution of revenues implied by the
bidding strategies in equation (1).
The expectation and variance of revenue presented in equations (2a) and (2b) were derived
for a single auction in which the bidders’ WTP is v. In our empirical analysis, we calculate
expected revenues by averaging revenues of auctions that were conducted during the period from
August 2007 to March 2009. Similarly, the variance is estimated by the sample variance of
revenues from auctions in that period. Because the WTP changed over that period, the relevant
benchmarks are not the conditional moments in equations (2a) and (2b) but the unconditional
expectation and variance given by the following:2
(3a)
(3b)
where E(v) and Var(v) are the expectation and the variance of the WTP, respectively.
The data sets analyzed below include ascending auctions with per-bid price increments of
d = €0.01 and d = €0.10. Therefore, we seek to determine the effect of a change in d on revenues.
From equations (3a) and (3b), we obtain the following predictions:
Prediction 1: An increase in the price increment d reduces the variance of auctioneer revenues in
ascending pay-per-bid auctions.
Prediction 2: An increase in the price increment d leaves the expected revenue in ascending pay-
per-bid auctions unaffected.
2 Here, we use the result that .
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3.3. Economic Analysis of Descending Pay-per-Bid Auctions
For the descending auction, we adapt the theoretical model by Gallice (2011), such that the
assumptions are the same as in the theoretical model by Augenblick (2012) and Platt et al.
(2013). We show below that the main results of Gallice (2011) are not affected by this
modification.
The descending pay-per-bid auction begins at a price, s, which is usually equal to the current
retail price (CRP). The starting price is publicly observable. Each bid decreases the current
auction price by e and costs b. The bidding costs are greater than the price decrement, b > e.3 In
contrast to the ascending auction, the current auction price is not publicly observable. Only the
current bidder can view this price. After observing the current auction price, the bidder can
decide whether to buy the product or not. If she decides to buy, then she pays the current auction
price, and the auction ends. If she decides not to buy, then the auction continues. The other
bidders do not know whether and how often someone has observed the price. Otherwise, a bidder
could count the number of times that the price has been observed and would know the current
price.
Gallice (2011) studies a descending pay-per-bid auction, assuming that bidders have
independently distributed private valuations for the product that is for sale. He shows that when
the highest valuation of a bidder is below the starting price, no bidder will place a bid. We build
on his theoretical model, but in contrast to Gallice (2011), we assume that bidders have
commonly known valuations for the products auctioned and, hence, a common WTP, v, that is
known. If the starting price is excessively high, i.e., v < s - e + b, then no bidder will see the
price, and the product will not be sold in equilibrium. If the starting price is sufficiently low, i.e.,
3 If b were smaller than e, then a bidder could observe the price v/e times and buy for a price of 0. The total bidding
costs of this strategy would be bv/e, which is smaller than the WTP v, given that b < e.
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v > s - e + b, then all bidders will want to see the price, and the first bidder who does so will buy
the product. The highest starting price that attracts participation by rational bidders is = v + e -
b. If a bidder places a bid, then she pays b and observes the price - e = v - b. Thus, the
maximum revenue per auction that the auctioneer can extract from rational bidders is .4
Note that for a given common WTP v, the auctioneer’s revenue in descending auctions is
deterministic. However, as for the ascending auction, the relevant benchmarks for our empirical
results are the unconditional expectation and variance:
(4a)
(4b)
Note that the starting price in the descending pay-per-bid auctions in our data set is the CRP.
We assume that the WTP is equal to the CRP. Because of the bidding cost, the CRP is slightly
above the maximum starting price .5 This characteristic implies that in equilibrium, we should
expect no bids in the descending auctions. This result is clearly at odds with the empirical results
of real descending pay-per-bid auctions in which we observe active participation.
The fact that bidders observe the price although the starting price is above can be explained
by considering their curiosity. If a bidder is curious about the hidden value of the price, then she
might receive some additional utility from lifting the veil and observing the price. If this
additional utility is greater than the difference of bidding costs and price decrement, b-e, then a
curious bidder will place a bid. Even when all bidders are rational (i.e., not curious) but believe
that some bidders are curious, it is rational to participate because curious bidders might have
4 The formal presentation of the equilibrium of the descending pay-per-bid auction and the proof are given in
Appendix A.
5 For the descending auctions in our data set, bidding costs are b=0.49, and the price decrement is e=0.40. Thus, the
maximum starting price is =CRP-0.09, which is slightly below the actually chosen starting price, which is equal to the CRP.
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placed a bid already and it would thus be profitable to place the next bid.6 However, because the
difference between the true starting price and the maximum starting price is minuscule
compared to the average CRP of the products sold in descending pay-per-bid auctions (€153.48),
we assume that the auctioneer sets the maximum starting price at .
It is easy to observe from equations (4a) and (4b) that the bidding costs, b, and the price
decrement, e, do not affect expected revenue and the variance of revenue. Unfortunately, neither
the bidding costs nor the price decrement was altered during the time period that our sample
encompasses. Therefore, there are no descending auction counterparts to Predictions 1 and 2 for
ascending auctions.
3.4. Theoretical Comparison of Ascending and Descending Pay-per-Bid Auctions
Having derived the revenues for both auction formats, we can now compare revenues per
auction and their variance for ascending and descending pay-per-bid auctions. Examining
equations (3a) – (4b), we obtain the following predictions:
Prediction 3: The variance of an auctioneer's revenue per auction is higher in ascending pay-per-
bid auctions than in descending auctions.
Prediction 4: Ascending pay-per-bid auctions generate the same expected revenues as descending
auctions.
4. Empirical Study of Ascending Auctions
Based on our economic analyses of ascending and descending auctions, we now aim to
empirically test our predictions (1-4) by comparing the expected revenues (serving as a
benchmark) derived from the theoretical model with actual revenues and by explaining the
resulting differences.
6 The websites of descending pay-per-bid auctioneers display the results of past auctions. Bidders can observe that
past auctions attracted bids and that the product was finally sold at a price below the current retail price. Thus, a rational bidder can conclude that there must be some curious bidders.
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In the following, we will first analyze ascending and descending auctions separately (Section
4 and 5). In Section 6, we will study the differences between ascending and descending pay-per-
bid auctions.
4.1. Data
We collected data from a European ascending pay-per-bid auctioneer that provided us with
two unique data sets. In contrast to a platform such as eBay that includes three parties
(auctioneer, buyer, and seller), the auctioneer is also the seller. Additionally, the auctioneer sells
only brand new products that are currently available at retailers (i.e., common collectibles). Used
products and older-generation products are not auctioned.
The first data set (A1) contains the results of all ten-cent (N=42,042) and penny (N=1,112)
ascending auctions from December 2007 to November 2008 (43,154 auctions in total). For each
completed auction, we received information about what product was auctioned, the final price,
the current retail price (CRP), the end time and the number of bids placed by the winners of the
auction. All auctions start at a price of €0.00, and each bid costs €0.50.
The second data set (A2) contains the results of 1,460 ascending auctions completed in March
2009, plus additional information regarding the bidding histories of these auctions, including
949,750 bids and their respective bidders. Data set A2 also includes information regarding the
participating bidders beyond these bids, such as their overall bidding experience with the
auctioneer (e.g., the number of auctions won, the number of auctions participated in) and
demographic information.
The two data sets differ in their numbers of auctions and in the details that are provided for
each auction. Data set A1 contains considerably more auctions, whereas data set A2 provides
more details regarding all bids (e.g., bidding time, nickname of bidder) and information regarding
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bidders beyond their behavior in these auctions (their first bidding date, the number of auctions
with bids placed, the number of auctions won, total bids placed, gender and age).
All data sets include information on the auction end time, the nickname of the winner, the
number of bids made by the winner, the total number of bids made (by the winner and the losers),
the product sold and its CRP. According to the auctioneer, the CRP represents an average price
value for the product on the basis of other online retailers. Table 2 provides an overview of the
product categories of the auctioned products from both data sets.
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Table 2
Description of the Data Sets
Product Category Typical Products in Category
Ascending Auction
(A1)
Ascending Auction
(A2)
# Ten-Cent
Auctions
# Penny
Auctions
# Ten-Cent
Auctions
# Penny
Auctions
Video Game Console Nintendo DS, Nintendo Wii, PSP, PS3, Xbox 360 10,465 1 422 0
Software Programs, PC games, Video games 8,949 1 244 0
Computer Accessories USB, Computer bags, Keyboards 4,332 1 185 0
Jewelry Watches, Bracelets 3,231 1 48 0
Computer Hardware Desktop, Notebook, Printer, Monitors 2,585 440 0 71
Home Appliances Coffee machine, Washer, Dental care, Shaver 2,230 13 38 0
Small Electronic Goods Mobiles, Telephones, Digital frame, Modem 2,102 28 0 38
Perfume Roma, D&G, Hugo Boss, Calvin Klein 1,407 0
Toys Lego, Fisher-Price 1,389 0
Fast-Moving Electronic
Appliances Mp3, Digital Camera 1,191 11 66 0
GPS Falk, Navignon, TomTom 623 480 0 45
DVD Blockbuster, TV series 922 0
TV + Audio-visual Samsung, LG, Philips 627 133 7 30
Housewares Cutlery, Pots 407 0
Cash Cash and 5 kg Gold 11 0
Vouchers iTunes 25 €, 150 Free Bids, 300 Free Bids 43 0 0 266
Others Bags, Key Rings 1,528 3
TOTAL 42,042 1,112 1,010 450
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4.2. Comparison of Actual and Expected Revenues per Auction
First, we compare actual revenues and expected revenues. For all revenues, we calculate
the average revenues across all categories standardized by their CRP, i.e. we divided the
revenues per auction by the corresponding CRP. We use equation (2a) to calculate the
expected revenues and use a t-test to compare them with actual revenues. To perform the t-
test, we also apply the variances of standardized expected revenues from equation (2b). Table
3 depicts the standardized means of the actual and expected revenues per auction as well as
the percentage difference across all categories for both the ten-cent auctions and the penny
auctions. As noted above, we assume that the WTP is equal to the CRP. This assumption is
certainly valid for products such as vouchers or cash, as these products are of a defined value
that is common to everyone (i.e., every bidder values a €50 voucher or €50 in cash equally).
However, this assumption may also hold for the remaining products: all auctioned products
are brand new, are in their original packaging and are currently sold at competitive retailers.
Additionally, the CRP represents an average price value for each product from common
online retailers.
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Table 3
Comparison of Means of Actual and Expected Standardized Revenues per Auction from
Ascending Auctions
Product
Category
Ten-Cent Auction
Penny Auction
N Actual
Revenue
Expected
Revenue Δ-% N
Actual
Revenue
Expected
Revenue Δ-%
Cash 11 2.07 1.00 *** 107%
Voucher 43 0.98 1.00 n.s.
185 4.21 1.00 *** 321%
Video Game
Console 10,887 1.75 1.00 *** 75%
Fast-Moving
Electronic
Appliances
1,257 1.34 1.00 *** 34%
11 0.73 1.00 n.s.
Software 9,190 1.26 1.00 *** 26%
Computer
Hardware 2,579 0.94 1.00 *** -6%
510 1.77 1.00 *** 77%
DVD 922 0.94 1.00 n.s. -6%
GPS 623 0.91 1.00 ** -9%
525 1.58 1.00 *** 58%
Toys 1,389 0.90 1.00 *** -10%
Home
Appliances 2,266 0.90 1.00 *** -10%
13 0.76 1.00 n.s.
Perfume 1,408 0.87 1.00 *** -13%
Small
Electronic
Goods
2,096 0.86 1.00 *** -14%
66 1.31 1.00 ** 31%
TV + Audio-
visual 639 0.83 1.00 *** -17%
158 1.21 1.00 * 21%
Computer
Accessories 4,517 0.75 1.00 *** -26%
Housewares 407 0.74 1.00 *** -26%
Others 1,491 0.72 1.00 *** -28%
Jewelry 3,276 0.21 1.00 *** -79%
TOTAL 43,057 1.12 1.00 12% 1.557 1.90 1.00 *** 90%
Δ-%: percentage differences between the means of actual and expected standardized revenues; positive differences are
illustrated in green cells and negative differences in red. All revenues are standardized. Standardized revenue is defined as revenue / CRP; CRP: current retail price;
*** = p<0.01, two-tailed; ** = p<0.05, two-tailed; n.s. = not significant
First, observing only the categories with obvious common values (cash and voucher), we
find significant differences between the actual and expected revenues for the cash category.
Actual revenues are more than double with cash, meaning that the auctioneer sold e.g. €100
for €207. The deviation between actual and expected revenues for the voucher category is not
significant for ten-cent auctions. However, we do find significant and surprising differences
for this category in penny auctions: selling vouchers generated revenues that were sold for
four times above their expected value.
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For ten-cent auctions, the results in Table 3 illustrate that the auctioneer additionally
generated higher revenues per auction than expected in the video game console, fast-moving
electronic appliances and software categories. In the remaining categories, all revenues per
auction are significantly lower. One explanation may be that hedonic products, such as game
consoles, mp3 players (e.g., iPods), and video games, induce more emotions and consequently
more bids than utilitarian products such as home appliances or GPS devices.
However, in penny auctions, it is salient that the significant deviations from the expected
revenues are always in favor of the auctioneer. We do not find significant differences in the
fast-moving electronic appliances and electronic appliances categories. This may be due to the
low number of observations in these categories.
4.3. Explanations for Differences between Actual and Expected Revenues per Auction
To investigate these differences in greater detail, we conduct a regression analysis with
the difference in standardized revenues per auction ((actual revenue – expected
revenue)/CRP) as the dependent variable. Furthermore, we add a binary variable (penny
auction) to indicate whether an auction was a penny auction (value = 1) or a ten-cent auction
(value = 0) and account for the number of bidders in each auction and the type of category,
whether it is perceived as hedonic, utilitarian, or both hedonic and utilitarian. Additionally, we
investigate the role of average product value in each category (measured by the average CRP
in a category). Hence, the concept of hedonic and functional products, which was previously
tested as a reliable construct by Strahilevitz and Myers (1998), as well as the value of the
product (CRP) are used to explore potential differences in product categories (see Appendix).
Table 4 displays the results of the linear regression analysis of the ascending auction. We
use data set A2 only because A1 did not include information regarding the number of bidders
participating in each auction.
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Table 4
Drivers of Differences between Actual and Expected Standardized Revenues per Auction in
Ascending Auctions
Variable Parameter
Penny Auction 0.779 ***
Number of Bidders per Auction 0.013 ***
LN Current Retail Price -1.278 ***
Hedonic Category 0.422 **
Utilitarian Category -0.205 *
Hedonic & Utilitarian Categorya
Constant 6.044 ***
a: reference category
adj. R2 = 0.314, N = 1,337 Standardized revenue is defined as revenue / CRP; CRP: current retail price
*** = p<0.01, two-tailed; ** = p<0.05, two-tailed; * = p<0.10, two-tailed
The analysis includes 1,003 ten-cent and 334 penny auctions (123 auctions were excluded
because of missing values) and explains 31.4% of the variance in the dependent variable. In
contrast to theoretical models, which assume that the number of bidders has no influence,
Table 4 shows that a higher number of competing bidders leads to a higher difference between
actual and expected standardized revenues. As this number does not impact the expected
standardized revenues, it means that a higher number of bidders yields higher actual revenues
per auction, which benefits the ascending pay-per-bid auctioneer. This finding can be
explained by relaxing the assumption that all bidders know the exact number of participants.
Byers et al. (2010) show that the expected revenue exceeds its equilibrium level v if bidders
underestimate the true number of participants. Conversely, if bidders overestimate the number
of participants, the auctioneer’s revenue will decrease. A large (small) number of bidders in
our regression might pick up situations in which bidders underestimate (overestimate) the true
number of participants, therefore leading to higher (lower) actual revenue than expected.
We also find that those categories perceived as either only hedonic or both hedonic and
utilitarian (here, the reference category) additionally drive the auctioneer’s revenues. Thus,
hedonic categories may cause emotional arousal, which results in less rational bidding
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behavior and increased bidding efforts (Hirschman & Holbrook, 1982). Finally, more
valuable products (with higher CRPs), such as jewelry, negatively affect the relative
difference between actual and expected standardized revenues.
To understand this surprising result, we examine whether bidders increase the number of
bids in accordance with a higher product value (as measured by the CRP). The analysis shows
that the number of bids is highly correlated (r = 0.939) with the (log) product value (p < 0.01).
However, bidders only slightly increase their number of bids in accordance with a higher
CRP. More specifically, we find that the discount off the final price relative to the CRP is
positively correlated with the product value (r = 0.52). Thus, more valuable products are sold
at greater (percentage) discounts. Finally, small price increments (i.e., penny auctions)
positively affect auctioneers’ revenues. This finding is not surprising, as the results in Table 3
already suggest systematic differences between ten-cent and penny auctions with respect to
revenues. However, according to Prediction 2, revenues should be unaffected regardless of
varying changes in price. In the following section, we analyze Predictions 1 and 2 in greater
detail.
4.4. Comparison of Actual Revenues in the Context of Different Changes in Price
Our economic analysis suggests that an increase in the price increment per bid d reduces
the variance in auctioneers’ revenues (Prediction 1). Thus, in our data set, penny auction
revenues should exhibit wider variation than those of ten-cent auctions. Figure 2 shows the
distribution of revenues using the example of a GPS product (TomTom Go 930T, CRP =
€549, data set A1) that was auctioned off in both penny and ten-cent auctions.
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Figure 2 Distribution of Revenues per Auction (in Euro) for TomTom Go 930T at Penny and Ten-cent
Auctions
Figure 2 indicates that the variance differs between the two price increments. The
volatility of achieved revenues is much higher in penny auctions than in ten-cent auctions.
A two-group variance comparison test supports this indication (see Table 5). We compare
the variances of penny and ten-cent auctions across three product categories of data set A1
(GPS, Computer Hardware and TV/Audio-visual), in which we have at least 100 penny
auctions and ten-cent auctions. To attain comparability across the products, we again use
standardized revenues. We find that the variance of penny auctions is always significantly
greater (p < 0.01) than that of ten-cent auctions, thus supporting Prediction 1 from the
theoretical model.
To empirically compare the revenues per auction of penny and ten-cent auctions
(Prediction 2), we use a two-independent-sample t-test, which additionally accounts for the
unequal variances between the two price increments. In contrast to our predictions, we find
that the revenues of penny auctions are always significantly higher (p < 0.01) than the
revenues of ten-cent auctions. Thus, penny auctions may lead to rather unsteady revenues
compared with ten-cent auctions but appear to be more profitable for the auctioneer.
05
1015
Freq
uenc
y
0 1000 2000 3000 4000Revenues
Penny Auctions
01
23
45
Freq
uenc
y0 1000 2000 3000 4000
Revenues
Ten-cent Auctions
Mean: 897.18 Std. Dev: 833.20 N: 409
Mean: 636.14 Std. Dev: 421.71 N: 99
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Table 5
Comparison of Average Standardized Revenues per Auction and Variances of Penny and
Ten-Cent Auctions
Penny
Auction Ten-Cent
Auction Δ-%
N Meana
Std.
Dev. N Meana
Std.
Dev. Meana
Std.
Dev
GPS 480 1.57 1.48
623 0.91 *** 0.77 ***
72% 92%
Computer Hardware 440 1.83 1.89
2,585 0.94 *** 0.80 ***
95% 137%
TV + Audio 133 1.16 1.32
627 0.83 *** 0.75 ***
40% 75%
TOTAL 1,112 1.58 1.64 42,042 1.12 *** 1.02 *** 41% 61%
a: standardized revenues, defined as revenue / CRP; CRP: current retail price
Δ-%: percentage differences between the means and standard deviations of penny and ten-cent auctions
*** = p<0.01, two-tailed
5. Empirical Study of Descending Auctions
5.1. Data
We also received data (D1) from a descending pay-per-bid auctioneer, including all
completed auctions (1,460) from August 2007 to October 2008. Similar to A2, this data set
contains both the results of all auctions and the corresponding bidding histories (N=192,988).
Here, auctions began at the products’ CRPs and each bid, which cost €0.49, decreased the
price by €0.40. Information regarding the bidding fees, the change in price and the starting
price, the CRP, was publicly available; however, the current price was not publicly available.
After placing a bid (and paying the bidding fee), the current price of the product was shown to
the bidder. Viewing further updates of the current price required placing additional bids. The
bidders also had no idea about the number of competitors and the starting time of the auction.
Thus, they could not infer current prices.
Similar to the ascending auctions, only one seller auctions brand new products in original
packaging. Table 6 gives an overview of the auctioned products.
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Table 6
Description of Data Set (D1) with Descending Auctions
Product Category Products per Category Number of Auctions
Video Game Console Nintendo DS, Nintendo Wii, PSP, PS3, Xbox 360 126
Software Programs, PC games, Video games 69
Computer Accessories USB, Computer bags, Keyboards 208
Jewelry Watches, Bracelets 18
Computer Hardware Desktop, Notebook, Printer, Monitors 101
Home Appliances Coffee machine, Washer, Dental care, Shaver 105
Small Electronic Goods Mobile, Telephones, Digital frame, Radio 142
Perfume Hugo Boss, Lagerfeld 14
Toys Lego, Board games 64
Fast-Moving Electronic
Appliances Mp3, Digital camera 196
GPS Falk, Navignon, TomTom 26
DVD Blockbuster, TV series 81
TV + Audio-visual Samsung, LG, Philips 40
Housewares Fondue pots 16
Vouchers Free bids, 100€ voucher 161
Others Bags, Magazine subscription 93
TOTAL 1,460
5.2. Comparison of Actual and Expected Revenues per Auction
We again standardize all revenues and then compare actual revenues with expected
revenues that were derived from equation (4a) (see Table 7). We again assume that the WTP
is a given common value that is equal to the CRP.
The actual revenues indicate that the variance is significantly different from zero. This
result can be explained by fluctuations in the WTP or CRP over time (see equation (4b)).
However, the variance is also different from zero in the voucher category, in which we expect
the same common value over time. Thus, alternatively, bidders who seek to achieve a large
discount may not decide to buy the product when the WTP is lower than the price in the
auction. Rather, such bidders wait until the price decreases further, hoping that other bidders
will think similarly. Information regarding final prices, which is provided on the website, may
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support this behavior: knowing that other bidders do not directly buy when the price is below
their own WTP may convince bidders to wait as well or to place multiple bids.
Table 7 also shows that actual revenues are significantly higher than expected revenues in
all categories; on average, the descending pay-per-bid auctioneer generated higher revenues
with the auctions compared with selling the products at their CRP across all categories.
Table 7
Comparison of the Means of Actual and Expected Standardized Revenues from Descending
Auctions
Product Category N Actual
Revenue
Std.
Dev.
Expected
Revenue Δ-%
Vouchers 161 1.34 0.39 1.00 *** 34%
Perfume 14 1.24 0.37 1.00 ** 24%
Computer
Accessories 208 1.18 0.19 1.00 *** 18%
Toys 64 1.18 0.19 1.00 *** 18%
Others 93 1.18 0.17 1.00 *** 18%
DVD 81 1.18 0.09 1.00 *** 18%
Small Electronic
Goods 142 1.17 0.15 1.00 *** 17%
Software 69 1.16 0.09 1.00 *** 16%
Housewares 16 1.13 0.08 1.00 *** 13%
Home Appliances 105 1.13 0.12 1.00 *** 13%
Video Game
Console 126 1.12 0.10 1.00 *** 12%
Fast-Moving
Electronic
Appliances
196 1.12 0.09 1.00 *** 12%
Jewelry 18 1.09 0.10 1.00 *** 9%
TV + Audio-visual 40 1.08 0.11 1.00 *** 8%
GPS 26 1.08 0.08 1.00 *** 8%
Computer
Hardware 101 1.07 0.09 1.00 *** 7%
TOTAL 1,460 1.17 0.19 1.00 *** 17%
Δ-%: percentage differences between the means of actual and expected standardized revenues; positive differences are
illustrated in green cells. Standardized revenue is defined as revenue / CRP; CRP: current retail price;
*** = p<0.01, two-tailed; ** = p<0.05, two-tailed
Similar to the results of the ascending auction, the deviation of actual to expected
revenues is highest for the vouchers category. However, in contrast to the results of the
ascending auction, categories such as video game console or fast-moving electronic
appliances do not stand out.
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5.3. Explanations for Differences between Actual and Expected Revenues per Auction
To investigate the differences between actual and expected revenues per auction in
descending auctions, we again conduct a regression analysis with the difference in
standardized revenues ((actual revenue – expected revenue)/CRP) as the dependent variable.
Furthermore, we account for the number of bidders in each auction, the type of category and
the average product value. Table 8 displays the results of the linear regression analysis of the
descending auctions.
Table 8
Drivers of Differences between Actual and Expected Standardized Revenues per Auction in
Ascending Auctions
Variable
Parameter
Number of Bidders per Auction 0.002 ***
LN Current Retail Price -0.085 ***
Hedonic Category -0.022 **
Utilitarian Category
0.006 n.s.
Hedonic & Utilitarian Categorya
Constant 0.483 ***
a: reference category
adj. R2 = 0.186, N = 1460
Standardized revenue is defined as revenue / CRP; CRP: current retail price
*** = p<0.01, two-tailed; ** = p<0.05, two-tailed; n.s. = not significant
Our estimation includes 1,460 auctions and explains 18.6% of the variance of the
dependent variable. The results reveal that the number of bidders in each auction significantly
affects revenue differences. Actual revenues increase with the number of bidders because the
number of bidders do not impact expected revenues. Thus, the number of bidders affects the
revenues per auction in both ascending and descending auctions.
Furthermore, purely hedonic product categories negatively affect revenue per auction
(compared with the reference category, hedonic and utilitarian). A possible explanation for
this finding is that in descending auctions, bidders may encounter an increasing trade-off
between ownership and additional savings. If the bidder has a strong desire to own the
product, then she will buy earlier, thus leading the actual revenues to converge with the
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expected revenues. If, however, the bidder is interested in obtaining a large discount, then she
will wait until there are sufficient bids. By contrast, in ascending auctions, there exists a
longer period in which the bidders can seek to attain both ownership and a large discount.
Bidders who seek to buy hedonic goods most likely fear that another bidder could buy the
product first. Finally, more valuable products negatively affect auctioneer revenues.
6. Comparison of Revenues of Descending Auctions and Ascending Auctions
Having analyzed ascending and descending pay-per-bid auctions separately, we now turn
to the comparison between the two auction formats. When comparing two auction formats in
the field, one ideally wants to compare them under the same conditions (e.g., by keeping the
set of bidders and products constant). This comparability is easier to achieve in laboratory
experiments, but that increase in internal validity could come at the expense of external
validity. Our field data provide advantages with respect to external validity but also provide
some challenges, as the comparison between auction formats may be confounded by
differences in the sets of bidders and products.
We aim to limit the effect of those unobservable differences by selecting two auction
websites that operate in the same geographic region, namely, Germany. We also restrict our
comparisons to auctions from the same period of time, namely, December 2007 to October
2008. Moreover, we focus on identical products (vouchers, iPods, video game consoles, and
USB sticks) that were sold sufficiently often on both auction websites (more than 40 times).
As a result, both auction websites address potential bidders who live in the same
geographic region and are interested in buying the same products during the same period of
time. The bidders then self-select themselves into one (or maybe both) of these auction
formats. Thus, although we control for many effects, self-selection may still affect our results.
Our comparison measures differences between the two auction formats under the condition
that bidders can freely choose between the two auction formats. This difference is still
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relevant information for auctioneers, as they must also consider the self-selection decisions of
bidders.
Our economic analysis suggests that the revenues of ascending auctions and descending
auctions are equal (Prediction 4) and that the variance of descending auctions is lower than
the variance of ascending auctions (Prediction 3).
Table 9
Comparison of Mean Standardized Revenues and Variances of Ascending and Descending
Auctions
Ascending Auction Descending Auction Δ-% in
Means
Δ-% in
Variance N Mean
a
Std.
Dev. N Meana
Std.
Dev.
Voucher 43 0.98 0.69 111 1.22 0.02 -20% *** 3,977% ***
Video Game Console 9,376 1.73 1.06 66 1.09 0.09 59% *** 1,117% ***
iPod 607 1,46 0.95 130 1.11 0.09 31% *** 942% ***
USB Stick 1,984 0.73 0.65 69 1.13 0.09 -35% *** 645% ***
a: standardized revenue, defined as revenue / CRP; CRP: current retail price
Δ-%: percentage differences between the means of ascending and descending auctions *** = p<0.01, two-tailed
Table 9 displays the standardized revenues and variances across four identical products
that were sold on both websites from December 2007 to October 2008, taken from data sets
A1 und D1. All ascending auctions are ten-cent auctions. Consistent with our expectations,
variances are significantly higher in ascending auctions than in descending auctions. This
result holds across all observed categories. In the voucher category, the standard deviation is
nearly forty times higher in ascending auctions.
Figure 3 illustrates these strong deviations using the example of iPods. For the ascending
auction, the scale of the x-axis begins at zero because there are numerous auctions in which
the achieved revenues are smaller than the CRP. In contrast, the scale begins at 1 for
descending auctions, where revenues are at least as high as the CRP. The scale ends at 5 for
ascending auctions; hence, in some auctions, revenues are five times as high as the CRP. The
maximum standardized revenue for descending auctions is reached with revenues that are 1.3
times higher than the CRP.
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Figure 3
Distribution of the Standardized Revenues of Ascending and Descending Auctions for iPods
Standardized Revenues = Revenue per Auction / Current Retail Price
Thus, ascending pay-per-bid auctions are associated with higher risks but result in a much
wider range of standardized revenues. The results in Table 9 also indicate that the revenues of
this specific category (iPods) are even significantly higher in ascending auctions than in
descending auctions. This finding contradicts Prediction 4, which posited revenue
equivalence. Table 9 shows that the reverse is true for vouchers and USB sticks. Here,
standardized revenues are 20% to 35% lower in ascending auctions. However, standardized
revenues for video game console and iPods, defined as revenues relative to the CRP, are
significantly higher in ascending ten-cent auctions, ranging from 37% to 59% higher in the
video game consoles category.
The differences in our results may again be explained by category differences. As we have
previously shown, the increased revenues for hedonic products such as video game consoles
and iPods in ascending auctions may be caused by irrational bidding behavior resulting from
emotional arousal or overestimation of bargain. In contrast, hedonic products result in
decreased revenues in descending auctions. Here, we expect that if the bidder has a strong
desire to own a product, then she will buy early for fear of another bidder taking the product.
020
4060
Freq
uenc
y
0 1 2 3 4 5
Standardized Revenues
Ascending Auction
010
2030
4050
Freq
uenc
y1 1.05 1.1 1.15 1.2
Standardized Revenues
Descending Auction
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7. Summary, Implications and Future Research
7.1. Summary of Results
The objective of this paper was to theoretically and empirically analyze the economic
effects of alternative formats of pay-per-bid auctions, in particular different auction formats
(ascending versus descending auction) and different price increments (one-cent versus ten-
cent auctions). For this purpose, we adapted and extended existing theoretical models on pay-
per-bid auctions, formulated predictions regarding auctioneers’ revenues and tested them
empirically with three large, unique data sets.
Analyzing ascending pay-per-bid auctions, we found that an increase in the price
increment for each bid reduces the variance of the auctioneer’s revenue, confirming our
prediction: a higher change in price increment reduces the risk that is associated with selling
the product. We found that the use of ten-cent auctions yields revenues per auction that are
less volatile and consequently less risky than the use of penny auctions.
However, penny auctions led to higher revenues per auction compared with ten-cent
auctions. In contrast to Prediction 2, our analysis provides evidence that an increase in the
price increment affects the expected revenue.
We further explained the observed differences between the actual revenues and the
expected revenues that were derived from the theoretical model, and we found that factors
such as the number of bidders and the type of the product category (whether hedonic or
utilitarian) are drivers of these differences.
Our empirical data set of descending pay-per-bid auctions did not include different price
increments; thus, we could not determine their economic effects. However, the data showed
differences between actual revenues and expected revenues. Again, the number of bidders and
the characteristic of the category (hedonic or utilitarian) were found to affect these
differences.
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Finally, we compared ascending and descending pay-per-bid auctions. Confirming
Prediction 3, we found that the variance of the revenue per auction is higher in ascending
auctions than in descending auctions. However, in contrast to Prediction 4, which postulated
revenue equivalence between ascending and descending pay-per-bid auctions, we found
significant differences in revenues per auction.
The theoretical model helps to place our empirical results into perspective. Average
revenues per auction above the CRP are not supported by the predictions of the theoretical
model. Consequently, average revenues are the result of a consumer behavior that is not
consistent with the theoretical model, such as non-equilibrium play, the overvaluation of
products, risk-loving preferences or other forms of behavior that are inconsistent with our
assumptions. However, all these phenomena may be transitory. The longer these new auction
formats are available, the more experience users obtain. Ultimately, individuals may learn to
play the equilibrium. Risk-seeking shoppers may move on to newer entertainment shopping
venues. Irrational individuals could learn to act more rational in pay-per-bid auctions or avoid
them altogether. Therefore, our empirical findings should be interpreted with caution because
average revenues above CRP may not be sustainable over a long period.
7.2. Implications
Our findings provide a number of implications for marketers and researchers. First,
auctioneers can use the findings from our study to consider different auction formats that may
improve their revenues. For ascending pay-per-bid auctioneers, our results indicate that penny
auctions yield higher revenues per auction but are also associated with higher risks. Thus, an
ascending auctioneer must weigh the individual advantages and disadvantages of such a
method. Our results further imply that an ascending pay-per-bid auctioneer may benefit from
a higher number of bidders and may benefit from selling products in hedonic categories rather
than utilitarian categories in the short term. Thus, such an auctioneer could make a greater
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effort to enhance traffic (e.g., through advertising) and to auction off more hedonic products
than utilitarian products.
On the contrary, our results suggest that a descending pay-per-bid auctioneer should sell
utilitarian products rather than hedonic products in their auctions. Auctions with hedonic
products end earlier, leading to lower revenues per auction.
Finally, we would recommend that auctioneers who cannot decide between ascending
and descending formats should choose the descending format when they are risk-averse and to
choose an ascending format when they are less risk-averse because the latter method offers
potential for a much wider range of revenues.
7.3. Future Research
A crucial question that is beyond the aim of this paper would involve determining how
long the differences between actual and expected revenues occur. Although our data sets
cover a period of up to one year, this period may be too short to fully capture bidders'
learning. Such learning would reduce the differences between actual and expected revenues
per auction. Future research may thus aim to analyze the development of the observed
differences over time.
Additionally, our comparison of the revenue per auction between ascending and
descending pay-per-bid auctions could not fully separate the effect of the auction format from
the self-selection effect of bidders. Although the difference that includes both effects is
relevant information for auction providers, future research may be capable of better
distinguishing these effects.
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Appendix A: Equilibrium of the Descending Pay-per-Bid Auction
In this appendix we prove that the following strategies constitute a subgame perfect
equilibrium: (i) The auctioneer chooses the starting price s=v+e-b. (ii) All bidders want to
place a bid if s≤ v+e-b. If the starting price is above v+e-b, no bidder wants to place a bid.
(iii) Once a bidder observes the price she buys the product and the auction ends.
Proof of part (iii). Suppose all players except bidder j follow the equilibrium strategies
given above. Assume first that bidder j is the first bidder who observes the price. She observes
the price v-b. The starting price is v+e-b and bidder j’s bid reduces this price by e. Since she
values the product at v, buying the product gives her utility of b. If she does not buy the
product, then the next bidder who observes the price will buy it and bidder j will receive
nothing. Thus, there is no profitable deviation for bidder j. Assume now that bidder j is not the
first to observe the price. Then, the utility from buying the product is greater than b, whereas
the utility from not buying is still 0. Again, there is no profitable deviation for bidder j.
Proof of part (ii). Suppose that all players except bidder j follow the equilibrium strategies
given above. If bidder j places a bid, observes the price and buys the product, then she
receives a utility of v-(s-e)-b. The first part of this expression is the value of the product, the
second is the price bidder j pays and the last part is the bidding fee. When bidder j acquires
the opportunity to observe the price, she must be the first bidder to observe the price, as part
(iii) tells us that otherwise, the auction would have ended already. Not bidding yields a utility
of zero. Thus, bidder j wants to place a bid, if v-(s-e)-b≥0 which can be rewritten as s≤ v+e-b.
Proof of part (i). Suppose that all bidders follow the equilibrium strategies given above.
The auctioneer’s revenue is s-e+b, if s≤ v+e-b and 0, otherwise. This revenue is maximized
for s=v+e-b and the maximum revenue is equal to v.
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Appendix B: Description of Scales and Categorization of Products
To categorize products as hedonic or utilitarian, we surveyed a sample of 86 people and
asked our respondents to classify the products as hedonic or utilitarian products. For this
purpose, we introduced the respondents to the concept of hedonic and utilitarian products and
asked them to classify the products according to the method of Strahilevitz and Myers (1998)
as utilitarian (practical), hedonic (frivolous), both utilitarian and hedonic, or neither utilitarian
nor hedonic. The classification of products was then based on the modal classification of the
respondents.
Categorization of Hedonic/Utilitarian Products
Product Current retail
price in €
Categorization of product as
hedonic utilitarian
Nintendo Wii 172 1 0
Apple iPod Touch 142 1 1
Nintendo WiiFit 71 1 0
Nintendo DS Lite 107 1 0
TomTom GO 740 399 0 1
Nikon D90 Camera 992 1 1
Kaspersky Internet Security 35 0 1
Phillips Full HD TV 1,269 1 0
Braun Oral-B Triumph 121 0 1
Panasonic KX 74 0 1
Acer Aspire 1,000 1 1
Samsung SGH-i900 601 1 1
Rothenschild Kryptonite 236 0 1
Kingston Data Traveler 32GB 59 0 1
Voucher 50 bids 25 0 1
1: yes; 0: no
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REFERENCES
Amaldoss, W., & Jain, S. (2008). Joint Bidding in the Name-Your-Own-Price Channel: A
Strategic Analysis. Management Science, 54(10), 1685-1699.
Amann, E., & Leininger, W. (1995). Expected Revenue of All-Pay and First-Price Sealed-Bid
Auctions with Affiliated Signals. Journal of Economics, 61(3), 273-279.
Amann, E., & Leininger, W. (1996). Asymmetric All-Pay Auctions with Incomplete
Information: The Two-Player Case. Games and Economic Behavior, 14(1), 1-18.
Augenblick, N. (2012). Consumer and Producer Behavior in the Market for Penny Auctions:
A Theoretical and Empirical Analysis. Working Paper. Available at:
http://faculty.haas.berkeley.edu/ned/Penny_Auction.pdf.
Bapna, R., Jank, W., & Shmueli, G. (2008). Consumer Surplus in Online Auctions.
Information Systems Research, 19(4), 400-416.
Barrot, C., Albers, S., Skiera, B., & Schäfers, B. (2010). Vickrey vs. eBay: Why Second-price
Sealed-bid Auctions Lead to More Realistic Price-Demand Functions. International
Journal of Electronic Commerce, 14(4), 7-38.
Byers, J. W., Mitzenmacher, M., & Zervas, G. (2010). Information Asymmetries in Pay-Per-
Bid-Auctions. Paper presented at the ACM Conference on Electronic Commerce,
Harvard University, Massachusetts.
Caldara, M. (2012). Bidding Behavior in Pay-to-Bid Auctions: An Experimental Study.
Working Paper. Available at: http://www.chapman.edu/research-and-
institutions/economic-science-institute/_files/BrownBag/michaelcaldera2012.pdf
Dholakia, U. M., Basuroy, S., & Soltysinski, K. (2002). Auction or Agent (or both)? A Study
of Moderators of the Herding Bias in Digital Auctions. International Journal of
Research in Marketing, 19(2), 115-130.
Gallice, A. (2011). Price Reveal Auctions on the Internet. Working Paper. Available at:
http://www.andreagallice.eu/PRAs%202011.pdf.
Haruvy, E., & Popkowski Leszczyc, P. T. L. (2009). Bidder Motives in Cause-related
Auctions. International Journal of Research in Marketing, 26(4), 324-331.
Hinnosaar, T. (2010). Penny Auctions are Unpredictable. Working Paper. Available at:
http://toomas.hinnosaar.net/pennyauctions.pdf.
Hinz, O., & Spann, M. (2008). The Impact of Information Diffusion on Bidding Behavior in
Secret Reserve Price Auctions. Information Systems Research, 19(3), 351-368.
Hirschman, E. C., & Holbrook, M. B. (1982). Hedonic Consumption: Emerging Concepts,
Methods and Propositions. Journal of Marketing, 46(3), 92-101.
Jap, S. D., & Naik, P. A. (2008). BidAnalyzer: A Method for Estimation and Selection of
Dynamic Bidding Models. Marketing Science, 27(6), 949-960.
Pinker, E. J., Seidmann, A., & Vakrat, Y. (2003). Managing Online Auctions: Current
Business and Research Issues. Management Science, 49(11), 1457-1484.
Platt, B. C., Price, J., & Tappen, H. (2013). The Role of Risk Preferences in Pay-to-Bid
Auctions. Management Science, forthcoming.
Reiner, J., Natter, M., & Skiera, B. (2014). Buy-Now Features in Pay-Per-Bid Auctions.
Journal of Management Information Systems, forthcoming.
Reiner, J., Brünner, T., Natter, M., & Skiera, B. (2014). Using Cumulative Prospect Theory to
Explain Why Bidders Participate in Pay-per-Bid Auctions. Working Paper.
Shubik, M. (1971). The Dollar Auction Game: a Paradox in Noncooperative Behavior and
Escalation. Journal of Conflict Resolution, 15(1), 109-111.
Spann, M., Skiera, B., & Schäfers, B. (2004). Measuring Individual Frictional Costs and
Willingness-to-Pay via Name-Your-Own-Price Mechanisms. Journal of Interactive
Marketing, 18(4), 22-36.
Forthc
oming
IJRM V
olume 3
1 #4 (
2014
)
38
Strahilevitz, M., & Myers, J. G. (1998). Donations to Charity as Purchase Incentives: How
Well They Work May Depend on What You Are Trying to Sell. Journal of Consumer
Research, 24(March), 434-446.
Tullock, G. (1980). Efficient Rent-Seeking. In J. M. Buchanan, R. D. Tollison & G. Tullock
(Eds.), Toward a Theory of the Rent-Seeking Society (pp. 97-112). College Station:
Texas A & M Univ. Press.
Wang, Z. & Xu, M. (2013). Selling a Dollar for more than a Dollar? Evidence from Online
Penny auctions. RFF Discussion Paper. Available at:
http://www.rff.org/RFF/Documents/RFF-DP-13-15.pdf.
Forthc
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